Removing and installing brake pressure regulator Adjusting brake pressure regulator

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Vanessa Clark
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1 Page 1 of 5 Removing and installing brake pressure regulator Adjusting brake pressure regulator Special tools and workshop equipment required 3255 Adjusters 3257 Socket, 27 mm AF V.A.G 1310 A Brake system tester Brake pressure regulator basic setting If, for example, one or both wishbones are replaced and no markings are given for the installation position of the spring mounting -2- on the wishbone, it is recommended that the basic setting is carried out, as described below. If basic setting is not necessary => Page fine adjustment of brake pressure regulator. Remove both shock absorbers. => Running gear, axles, steering from January 1996; Repair group 42; Servicing rear suspension; Removing and installing shock absorbers Insert special tool 3255 and pretension wishbone => Page

2 Page 2 of 5 Align beam -4- horizontally by eye, to do this turn both buffer stops -1- onto stop on horizontal beam -4- (no preload at buffer stop -1-). Move a spring mounting -2- down until a gap (arrow) of approx. 2 mm exists on the opposite side between buffer stop -1- and horizontal beam Move second spring mounting -2- down until the beam -4- is again horizontal. Turn both buffer stops -1- fully back, so that the largest possible gap exists between horizontal beam -4- and buffer stop. Continue with fine adjustment of brake pressure regulator => Page Brake pressure regulator fine adjustment Remove both shock absorbers. => Running gear, axles, steering from January 1996; Repair group 42; Servicing rear suspension; Removing and installing shock absorbers Slide tubes 3255/1 onto adjusting device. Insert adjusting device 3255 with

3 Page 3 of 5 tubes 3255/1 as illustrated. Grease spindle thread, face of nut and washer surface with MoS2 grease. Insert a shock absorber rubber bush between the washer (arrow) and the wishbone in order to tension the wishbone. It is not permitted to use an impact screwdriver. First check buffer stop settings => Page If complaints of poor braking or over braking on the rear axle are received. Pretensioning wishbone to dimension -x- with special tool Washer 2 - Spring 3 - Wishbone The measurement is taken from the spring mounting steel plate edge (arrow a) to the top edge of the assembly hole in the wishbone (arrow b). Set dimension -x- according to table on Page The coil spring can be removed to adjust the wishbone to dimension -x-. Continue with brake pressure check => Page Checking brake pressure Connect the pressure gauge V.A.G 1310 to front left brake caliper and to rear left brake caliper. Bleed both gauges (bleeding brake system => Page ) Depress brake pedal and check pressures. Front axle 50 bar Rear axle 20 ± 2 bar Adjust if necessary => Page Continue with adjusting buffer stops => Page Adjusting brake pressure

Page 4 of 5 Turn both buffer stops -1- back onto stop (downward). Mark spring mounting -2- position with a felt tip pen or adhesive tape on the wishbone. Loosen bolt -3- and move mounting - 2-.

It is only necessary to adjust the position of the second spring mounting -2- if the horizontal beam - 4- is excessively inclined (more than 4 mm => arrows).

4 Page 4 of 5 Turn both buffer stops -1- back onto stop (downward). Mark spring mounting -2- position with a felt tip pen or adhesive tape on the wishbone. Loosen bolt -3- and move mounting Moving spring mounting -2- downwards - Increases pressure. Moving spring mounting -2- upwards - Decreases pressure. It is only necessary to adjust the position of the second spring mounting -2- if the horizontal beam - 4- is excessively inclined (more than 4 mm => arrows). Moving the spring mounting -2-1 mm equates to a pressure change of approx. 4 bar at the rear axle. Slight inclination of the horizontal beam -4- is permissible (max. 4 mm between left and right => arrows). Tighten bolt -3-, counter-hold when tightening. Correct brake pressure regulator setting at second spring mounting - 2- if necessary. Continue with adjusting buffer stops => Page Adjusting buffer stops Check whether the securing clip, item is securely seated. Check brake pressure (if not already checked)=> Page If the setting is in order, insert pedal depressor. Hold front axle brake pressure to at least 50 bar. Turn both buffer stops -1- up using 6 mm AF hexagon key (illustration shows only one buffer stop) until a gap of 0.5 mm can be measured using a feeler gauge -5- between both buffer stops -1- and

Page 5 of 5 horizontal beam -4-. Remove V.A.G 1310 and bleed brake system => Page 47-27. Remove special tool 3255. Install shock absorber.

5 Page 5 of 5 horizontal beam -4-. Remove V.A.G 1310 and bleed brake system => Page Remove special tool Install shock absorber. => Running gear, axles, steering from January 1996; Repair group 42; Servicing rear suspension; Removing and installing shock absorbers Table of brake pressure regulator settings Rear axle spring Colour coding Dimension x ± 1 mm L grey 238 mm A/C white 258 mm M pink 268 mm H/J orange 270 mm P light blue 270 mm violet 280 mm F K B opal green yellow redbrown 281 mm 284 mm 292 mm

Servicing front brakes

46-1 Servicing front brakes C54 brake caliper, servicing Special tools and workshop equipment required VAG 1331 Torque wrench (or equivalent) VAG 1410 Torque wrench (or equivalent) VAG 1869/2 Brake pedal